Counterbalanced drive for reciprocating cutter

ABSTRACT

A counterbalanced transmission drive for reciprocating the sickle of a mower. A rocker arm pivotally mounted intermediate its ends is oscillated by an eccentric. One end of the rocker arm connects with the sickle. The opposite end carries a counterweight. By this arrangement, the counterweight and the sickle oscillate in opposing directions.

[451 Mar. 12, 1974 United States Patent [1 1 Templeton 66 6 00 O M6 54656 7505 mm N mm m e i s oeM .laoa GNRC 4478 6666 9999 11.11 9981 62685993 8842 443 3333 Primary Examiner-Leonard l-l. Gerin [22] Filed:

Assistant ExamirierWesley S. Ratliff, Jr.

Attorney, Agent, or FirmWatts, Hoffmann, Fisher & Heinke Co.

T C A R T S B A 1 7 5 l 68 01 my 62 1 NF 4 7 z 4 4 7 [52] US. [51] Int.

[58] Field of i Z g?gb g2} 1 A counterbalanced transmission drive forreciprocating the sickle of a mower. A rocker arm pivotally RefrencesCited mounted intermediate its ends is oscillated by an ec- UNITEDSTATES PATENTS centric. One end of the rocker arm connects with thesickle. The opposite end carries a counterweight. By

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SHEET 2 UF 4 INVENTOR. WILLIAM E.TEMPLETON W, JJ M ATTORNEYS PATENTEDMAR 12 974 SHEEI 3 BF 4 2 we Q Q 7 miminwzwv slvesilo x SHEET ll 0F 4ATTORNEYS WILLIAM EQTEMPLE'I ON BACKGROUND OF THE INVENTION ance in onedirection while driving the sickle in the op posite direction. Manyproposed counterbalance drives utilize the momentum of the counterweightto provide added drive momentum in reversingthe direction of the sickle.In such arrangements, the counterweight acts as a flywheel. When thesickle becomes jammed by a foreign object, such drive momentum as isimparted to the sickle by the counterweight frequently causessubstantial breakage of or other damage to components of the cutter.

SUMMARY OF THE PRESENT INVENTION The present invention overcomes theforegoing drawbacks of the prior art and provides an improvedcounterbalanced drive system which is exceptionally simple andinexpensive in design and yet which overcomes the problems cuttercomponent damage due to counterweight momentum. The present inventionprovides a counterweight which is oscillate directly by the same rockerarm which oscillates the sickle. The counterweight is thereby caused toaccelerate and decelerate in an. identical fashion with-the sickle. Bythis arrangement the momentum of the counterweight will be seen to bezero at the instant of reversal of direction of the sickle. Hence thecounterweight does not act in the manner of a flywheel to impart acontinuous momenturn of its own to the sickle. Rather, during sicklereversal, both the sickle and the counterweight cease movement, and nomomentum is applied by the counterweight to effect sickle directionreversal.

Accordingly, the object of this invention is to provide a transmissionfor a mower having a novel and improved counterbalanced sickle drivesystem.

Other objects and a fuller understanding of the present invention may behad by referring to the following description and claims taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS cated-by the line 4-4 of FIG. .1;

FIG. 5 is a: motiondiagram illustrating the movement of the rocker armand counterweight; and,

FIG. 6 is a perspective view showing the connection between the rockerarm and the sickle head.

' DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, atransmission assembly is illustrated generally at 10. The transmissionincludes a housing 11. The major operating components disposed withinthe housing include a drive shaft 12 which carries an eccentric 13. Theeccentric is connected to a rocker arm 14 by a linkage 15. The rockerarm is pivotally mounted about a shaft 16 and comprises first and secondlegs l7, 18 extending in opposite directions from pivot shaft 16. Thefirst leg 17 extends downwardly for connection to a sickle in a mannerthat will be explained later in greater detail. The second leg 18extends upwardly and carries a counterweight 19. From the foregoingbrief description, it will be apparentthat rotation of the drive shaft12 will cause the eccentric 13 to oscillate the first and second rockerarm legs 17 and 18 in opposing directions.

Turning to a more detailed description of the transmission, andreferring particularly to FIG. 2, it will be seen that the housing 11comprises three cast iron members. Left and right housing members 20, 21have a central housing member 22 sandwiched between them. The enclosedarea between the housing members 20, 22 defines a'first operatingchamber 23, while the enclosed area between the housing members 21, 22defines a second operating chamber 24.

A hydraulic motor 25, the construction and arrangement of which is wellknown in the art, is secured to the left housing member 20. A motorshaft 26 extends into the chamber 23. through an opening 27 in the lefthousing member. A gear train including a drive pinion 28 and a meshinggear 29 serve to transmit rotational motion from the motor shaft 26 tothe drive shaft 12. Square keys 30, 31 respectively connect the drivepinion 28- to the motor sahft 26 and the gear 29 to the drive shaft 12.

The drive shaft 12 extends through the central housing member 22 fromthe chamber 23 to the chamber 24. The left end of the drive shaft 12 isrotatablysupported from the left housing member 20 by a roller bearing32. Similarly, the right end of the drive shaft 12 is rotatablysupported from the right housing member 21 by a roller bearing 33. Theshaft 12 is axially located by a pair of collars 34, 35 whichrespectively engage the inner races of the bearings 32, 33.

The collar 34 is slip fitted over the left end of the shaft 12. Thecollar 35 is rigidly secured to the right end of shaft 12 by means of apin 36. A nut 37 carried by a threaded portion 38 of the shaft 12engages the outer end of the collar 34. By tightening the nut 37, the

collar 34 is pressed into engagement with the bearing 32, and the collar35 is drawn into engagement with the bearing 33'. I

The axial travel of lubricant along the shaft 12 is controlled atseveral locations by the provision of a series of seals. The passage oflubricant Ieftwardly from the bearing 32 is prevented along the innerdiameter of the collar 34 by an O-ring 39 carried in an annular groove40 of the shaft 12. A seal 41 pressed into an annular recess 42- inhousing member 20 engages the outer diameter of collar 34. In similarfashion seals 43, 44 carried respectively by the housing members 21, 22engage the shaft 12.

A quanitity of lubricant, not shown, is normally maintained within thechamber 23 to lubricate the pinion 28 and the gear 29. This lubricantalso serves to lubricate the bearing 32. Lubricant for the bearing 33 iscarried in a chamber defined by a cover 46 secured to housing member 21.A grease fitting 47 is carried by the cover 46 to admit lubricant to thechamber 45.

The eccentric 13 comprises an inner member 48 secured to the shaft 12. Asquare key 49 is interposed between the shaft 12 and the inner member toprevent relative rotation. The inner member has a circular peripherywhich is eccentric with the shaft 12. An annular outer member 50 isjournaled rotatably on the inner member 48 by means of a roller bearing51.

y The inner member 48 carries a grease fitting 52. A first lubricantpassage 53 extends inwardly from the fitting 52 to the shaft 12. Anaxial groove 54 in shaft 12 communicates with the first passage 53 andwith a second lubricant passage 55. Second passage 55 is provided tocarry lubricant radially outwardly from the groove 54 to the bearing 51.

The transmission mechanism disposed in chamber 24 is best seen byreferring to FIGS. 3 and 4 in conjunction with FIG. 1. The linkage means15 may be seen to comprise a yolke 56 integrally formed with the outereccentric member 50. The yoke 56 comprises left and right legs 57, 58having aligned openings formed therethrough to accommodate a pin 59. Thepin 59 pivots within a pair of roller bearings 60 journaled in anaperture formed in the rocker arm 14. The pin 59 and the bearing 60thereby provide a pivotal connection between the linkage means 15 andthe rocker arm 14. As is best seen in FIG. 4, the bearings 60 arelubricated by means of a grease passage 61 which communicates with agrease fitting 62 carried by the rocker arm 14.

Referring primarily to FIG. 3, it will be seen that the pivot shaft 16has a threaded aperture 63 formed coaxially within its left and rightends. Cap screws 64 extend through left and right housing members 20, 21and into the threaded apertures 63. An annular flanged insert 65 ispositioned within an opening 66 in right housing member 21 to reduce thesize of the opening 66 to a size which will accommodate one of the capscrews 64. When the cap screws 64 are tightened, the shaft 16 issecurely held by the left and right housing members 20, 21.

A pair of roller bearings 67, 68 rotatably mount the rocker arm 14 aboutthe shaft 16. The first or lower leg 17 of the rocker arm 14 terminatesin a downwardly opening yoke 69. Aligned openings are formed in the yoke69 to accommodate a drive pin 70. The drive pin 70 is restrained fromaxial movement by means of a locking pin 71. Thelocking pin 71 pressfits into a cyliridrical opening 72 in the yoke 69, and into a groove 73formed in the pin 70. A square bearing block 74 is carried by the pin70. As will be explained later in greater detail, the bearing block 74is part of a connection means provided to drive the mower sickle.

The second or upper leg 18 of the rocker arm has a threaded openingformed therein. The counterweight 19 has a large recess 76 formedtherein to the upper end of the leg 18. An aperture 77 aligned with thethreaded aperture extends upwardly through the counterweight 19. A capscrew 78 extends through the aperture 77 and threads into the threadedaperture 75. The head 79 of the cap screw 78 engages a recessed shoulder80 formed within the aperture'77. By this arrangement, the counterweight19 may be pulled downwardly over the leg 18 by tightening the cap screw78. A set screw 81 is positional within a threaded aperture 82 whichextends laterally of the aperture 77. The set screw 81 engages the capscrew 78 to lock the cap screw securely in position. The upper end ofthe chamber 24 adjacent the eccentric is closed by an eccentric cover83, as best seen in FIG. 1. The lower end of the chamber 24 is providedwith an opening 84 formed through the right housing member 21. The lowerleg 17 and the yoke 69 of the rocker arm 14 extends through the opening84. v

As was previously mentioned, the lower leg 17 of the rocker arm 14drives a sickle. Referring to FIG. 6, a sickle 85 is seen to comprise asickle bar 86 to which are secured aplurality of sickle sections 87 anda sickle head 88. The sickle 85 is carried for reciprocation by a cutterbar assembly including a support bar 89 which mounts a plurality ofguards 90. Reciprocation of the sickle is limited to a planartranslatory movement during which the sickle sections 87 cooperate withledger plates (not shown) carried by the guards 90 to provide a cuttingaction.

As may be seen in the motion diagram of FIG. 5, the lower leg 17 ofrocker arm 14 transcribes an arcuate motion during the course of itsoscillation. The arcuate line 91 represents the path of motion of thedrive pin 70. However, the sickle 85 which is driven from the leg 17 islimited to a planar translatory movement as represented by the line 92.In order to translate the arcuate motion of the rocker arm into atranslatory planar motion, a connection means is provided including thebearing block 74. The sickle head 88 includes a cooperating, verticallydisposed, open ended slot 93 which slip fits over the bearing block 74.By this arrangement, as seen in FIG. 5, the bearing block 74 movesrelative to the slot '93 during its arcuate travel, whereby the sicklehead 88 is not deflected by the rocker arm during reciprocation.

Although the foregoing description is necesarily of a detailedcharacter, in order that the invention may be set forth, it is to beunderstood that the specific terminology is not intended to berestrictive or confining, and that various rearrangements of parts andmodification of detail may be resorted to without departing from thescope or spirit of the invention as herein claimed.

1. A power driven reciprocating cutter comrising:

a. a reciprocable sickle movable back and forth along a straight-linepath;

b. a rocker arm positioned to one side of said path and pivotallymounted for oscillating arcuate movement about a pivot axis;

0. drive means adapted for connection to a source of rotary motion anddrivingly connected to said rocker arm to oscillate said rocker armabout said pivot axis between first and second extreme positions, whichpositions establish the stroke of said rocker arm;

d. said rocker arm including a pair of legs extending in oppositedirections from said pivot axis;

e. one of said legs extending toward said sickle in a directionsubstantially perpendicular to said straight-line path when said rockerarm is near the center of its stroke;

f. a counterweight carried by the other of saidlegs;

g. connection means establishing a sliding driving connection betweensaid one leg and said sickle and being operative to effect a positivedriving movement of said sickle along said straight-line path withouttransmitting forces to said sickle transversely of said straight-linepath; and,

h. said connection means including a driving member carried by said oneleg for arcuate movement with said rocker arm, and a head carried onsaid sickle and slidably receiving said driving member.

2. The power driven cutter of claim 1 wherein said head has a pair ofparallel spaced surfaces formed thereon which slidably engage saiddriving member therebetween.

3. The power driven cutter of claim 2 wherein said surfaces extend inplanes substantially perpendicular to said straight-line path.

4. A power driven mowing machine comprising:

a. a reciprocable sickle;

b. a counterbalanced transmission comprising:

i. a housing structure;

ii. a drive shaft rotatably carried by said housing structure andadapted for connection to a sourc of rotary motion;

iii. a rocker arm pivotally carried by said housing structure andcomprising a pair of legs extending in opposite directions from thepivot axis of said rocker arm;

iv. oscillating drive means drivingly coupling said drive shaft to saidrocker arm to oscillate said rocker arm about said pivot axis inresponse to rotation of said drive shaft;

v. a counterweight carried by one of said legs for oscillating arcuatemovement with said rocker arm;

0. connection means establishing a positive driving connection betweensaid sickle and the other of said legs and being operative to transformthe arcuate oscillatory'movement of said other leg into straight-linereciprocatory sickle drive motion;

d. said connection means including a driving member carried by saidrocker arm and a slotted head carried by said sickle, said drivingmember being slidably received by said slotted head to establish asliding driving connection between said rocker arm and said sickle,which connection is operative to transmit driving forces to said sicklesubstantially only in directions paralleling the straight linereciprocation path of said sickle, whereby substantially no forces aretransmitted to said sickle which tend to deflect the sickle laterally ofits reciprocation path during reciprocation.

5. A reciprocating cutter comprising:

a. a reciprocable s'ickle movable back and forth along a straight-linepath;

b. a rocker arm pivotally mounted to one side of said path and having apair of legs extending in opposite directions from the pivot axis ofsaid rocker arm, one of said legs extending toward said sickle and theother of said legs extending away from said sickle;

c. drive means for oscillating said rocker arm through an arcuate strokeabout said pivot axis;

d. a counterweight carried on said other leg;

e. connection means establishing a sliding connection between said oneleg and said sickle, which connection is operative to transmit drivingforces only in directions paralleling said straight line path toreciprocate said sickle as said rocker arm oscillates; and,

f. said connection means including a driving member carried by said oneleg for arcuate movement with said rocker arm, and a head carried onsaid sickle and slidably receiving said driving member.

6. A reciprocating cutter comprising:

a. a reciprocable sickle movable back and forth along a straight-linepath;

b. counterbalanced transmission means adapted for connection to a sourceof rotary drive motion and operative to transform rotary drive motioninto oscillating motion along an arcuate path;

0. said transmission means including:

i. a housing structure;

ii. a drive shaft rotatably carried by said housing structure andadapted for connection to a source of rotary motion;

iii. an eccentric driven from said drive shaft;

iv. a rocker arm pivotally carried by said housing structure andcomprising first and second legs extending in opposed directions fromthe pivot axis of said rocker arm;

v. linkage means connecting said rocker arm to said eccentric such thatrotation of said drive shaft will operate said eccentric and willoscillate said rocker arm about said pivot axis;

vi. a counterweight carried by said second leg for movement therewith;and, i

d. connection means establishing a positive drive connection betweensaid one leg and said sickle and being operative to transform saidoscillating arcuate motion along saidarcuate path to straightline sicklereciprocating motion along said straightline path, said connection meansincluding a driving member carried by said one leg for arcuate movementwith said rocker arm, and a head carried on said sickle and slidablyreceiving said driving member whereby the connection established betweensaid transmission means and said sickle is operative to transmit drivingforces only in directions paralleling said straight-line path.

7. The reciprocating cutter of claim 6 wherein the interconnection ofsaid linkage means and said rocker arm is located intermediate saidpivot axis and the connection of said first leg to the sickle.

8. The mowing machineof claim 6 additionally including a hydraulic motordrivingly connected to said drive shaft.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,796,104Dated March 12, 1974;

William E. Templeton Inventor(s) 1 I It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 2, line 38, delete "sahft" and substitute Column 3, line 6l,after the word "to" insert accommodate 7 Column 1,51ine 48', delete"comr-i'sing" and substitute comprising Signed and sealed this 13th dayof Augustl9'7h.

(SEAL) Attest:

McCOY 1Y1. GIBSON, JR. v C. MARSHALL DANN Attesting Officer Commissionerof Patents fQRM PO-IQSQ (1 uscoMM-oc cove-P69

1. A power driven reciprocating cutter comrising: a. a reciprocablesickle movable back and forth along a straight-line path; b. a rockerarm positioned to one side of said path and pivotally mounted foroscillating arcuate movement about a pivot axis; c. drive means adaptedfor connection to a source of rotary motion and drivingly connected tosaid rocker arm to oscillate said rocker arm about said pivot axisbetween first and second extreme positions, which positions establishthe stroke of said rocker arm; d. said rocker arm including a pair oflegs extending in opposite directions from said pivot axis; e. one ofsaid legs extending toward said sickle in a direction substantiallyperpendicular to said straight-line path when said rocker arm is nearthe center of its stroke; f. a counterweight carried by the other ofsaid legs; g. connection means establishing a sliding driving connectionbetween said one leg and said sickle and being operative to effect apositive driving movement of said sickle along said straight-line pathwithout transmitting forces to said sickle transversely of saidstraight-line path; and, h. said connection means including a drivingmember carried by said one leg for arcuate movement with said rockerarm, and a head carried on said sickle and slidably receiving saiddriving member.
 2. The power driven cutter of claim 1 wherein said headhas a pair of parallel spaced surfaces formed thereon which slidablyengage said driving member therebetween.
 3. The power driven cutter ofclaim 2 wherein said surfaces extend in planes substantiallyperpendicular to said straight-line path.
 4. A power driven mowingmachine comprising: a. a reciprocable sickle; b. a counterbalancedtransmission comprising: i. a housing structure; ii. a drive shaftrotatably carried by said housing structure and adapted for connectionto a source of rotary motion; iii. a rocker arm pivotally carried bysaid housing structure and comprising a pair of legs extending inopposite directions from the pivot axis of said rocker arm; iv.oscillating drive means drivingly coupling said drive shaft to saidrocker arm to oscillate said rocker arm about said pivot axis inresponse to rotation of said drive shaft; v. a counterweight carried byone of said legs for oscillating arcuate movement with said rocker arm;c. connection means establishing a positive driving connection betweensaid sickle and the other of said legs and being operative to transformthe arcuate oscillatory movement of said other leg into straight-linereciprocatory sickle drive motion; d. said connection means including adriving member carried by said rocker arm and a slotted head carried bysaid sickle, said driving member being slidably received by said slottedhead to establish a sliding driving connection between said rocker armand said sickle, which connection is operative to transmit drivingforces to said sickle substantially only in directions paralleling thestraight line reciprocation path of said sickle, whereby substantiallyno forces are transmitted to said sickle which tend to deflect thesickle laterally of its reciprocation path during reciprocation.
 5. Areciprocating cutter comprising: a. a reciprocable sickle movable backand forth along a straight-line path; b. a rocker arm pivotally mountedto one side of said path and having a pair of legs extending in oppositedirections from the pivot axis of said rocker arm, one of said legsextending toward said sickle and the other of said legs extending awayfrom said sickle; c. drive means for oscillating said rocker arm throughan arcuate stroke about said pivot axis; d. a counterweight carried onsaid other leg; e. connection means establishing a sliding connectionbetween said one leg and said sickle, which connection is operative totransmit driving forces only in directions paralleling said straightline path to reciprocate said sickle as said rocker arm oscillates; and,f. said connection means including a driving member carried by said oneleg for arcuate movement with said rocker arm, and a head carried onsaid sickle and slidably receiving said driving member.
 6. Areciprocating cutter comprising: a. a reciprocable sickle movable backand forth along a straight-line path; b. counterbalanced transmissionmeans adapted for connection to a source of rotary drive motion andoperative to transform rotary drive motion into oscillating motion alongan arcuate path; c. said transmission means including: i. a housingstructure; ii. a drive shaft rotatably carried by said housing structureand adapted for connection to a source of rotary motion; iii. aneccentric driven from said drive shaft; iv. a rocker arm pivotallycarried by said housing structure and comprising first and second legsextending in opposed directions from the pivot axis of said rocker arm;v. linkage means connecting said rocker arm to said eccentric such thatrotation of said drive shaft will operate said eccentric and willoscillate said rocker arm about said pivot axis; vi. a counterweightcarried by said second leg for movement therewith; and, d. connectionmeans establishing a positive drive connection between said one leg andsaid sickle and being operative to transform said oscillating arcuatemotion along said arcuate path to straight-line sickle reciprocatingmotion along said straight-line path, said connection means including adriving member carried by said one leg for arcuate movement with saidrocker arm, and a head carried on said sickle and slidably receivingsaid driving member whereby the connection established between saidtransmission means and said sickle is operative to transmit drivingforces only in directions paralleling said straight-line path.
 7. Thereciprocating cutter of claim 6 wherein the interconnection of saidlinkage means and said rocker arm is located intermediate said pivotaxis and the connection of said first leg to the sickle.
 8. The mowingmachine of claim 6 additionally including a hydraulic motor drivinglyconnected to said drive shaft.